Radio antenna for automobiles



Nov. 30, 1937.

H. D. GEYER 2,100,643 RADIO ANTENNA FOR AUTOMOBILES Filed Sept. 9, 19352 Sheets-Sheet l @gw/MM IS ATTORNEY Nov. 30, 1937. H D @YER 2,100,643

RADIO ANTENNA FOR AUTOMOBILES Filed Sept. 9, 1935 2 Sheets-Sheet 2INVENTOR Har Vey .Geyer MY #di HIS ATToRNgS Cil Patented Nov. 30, 1937UNITED STATES PAT-ENT OFFICE Harvey D. Geyer, Dayton, Ohio, assigner toGeneral Motors Corporation, Detroit, Mich., a corporation of DelawareApplication September 9, 1935, Serial No. 39,712

6 Claims.

This invention relates to radio antennas designed especially forefficient mounting upon automobiles quite near the ground such as underthe running board thereof.

An object of this invention is to provide an efficient antenna which isinexpensive to make and very simply and easily installed at a suitableconstantly spaced distance from an automobile running board.

An important feature of the antenna of this invention is that it is verystrong and durable and not easily damaged by flying rocks orobstructions over which the automobile may pass and which will notaccumulate foreign matter such as dirt, water, ice, snow etc. This isdue to the desired antenna effect being obtained by using a relativelyfew laterally spaced reaches of a strong flat metal strip rather than byproviding the necessary antenna surface by using a Wide flat metal plateor by means of a much greater number of small metal wires or Wirenetwork. Such strong metal strips are very simply resiliently fastenedunder the running board in suitably laterally spaced relation and sincethese strips run essentially longitudinally with the running board `andnot cross-wise thereof there is much less chance of their catching uponany raised obstruction over Which the automobile may pass.

Another object of the invention is to provide an automobile antennawhich is completely physically protected andelectrically insulated withresilient water-repellant rubber whereby it retains a minimum of sand,mud, water or snow thrown thereupon and hence will have a substantialconstant capacity under all conditions and will continue to provide goodelectrical performance.

The rubber covering also protects the metal antenna against physicaldamage by flying sand or rocks or other road hazards.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

Fig. 1 is a plan View of a completely assembled antenna secured in placeupon the under side of the left running board of an automobile, thecentral portions of the antenna being broken away in order to show theparts on a larger scale.

Fig. 2 is a section taken on line 2-2 of Fig. 1.

Fig. 3 is a section taken on line 3-3 of Fig. 1.

Fig. 4 is a section taken on line 4`-4 of Fig. 1.

Figs. 5 and 6 show a modied form of this invention.

Fig. 5 shows a plan View of one end of the antenna assembly with all theparts necessary in the attachment of the antenna to the automobile.

Fig. 6 is a side view of Fig. 5 with a. portion thereof taken in sectionin line 6-6 of Fig. 5.

Similar reference characters refer to similar parts throughout theseveral views.

In the forms shown in Figs. 1 to 4 the antenna IU consists of arelatively strong flat strip of metal, preferably steel or brass, of thedesired length, completely encased in a Water-repellent soft rubbercovering II, as shown in Fig. 4. A steel strip one hundredth inch thickby three quarter inch wide is suitable. This part is pref* fera-bly madein continuous lengths by extruding a coating of uncured soft rubbercompound containing a wax, such as paraffin, upon the metal strip I andthereafter properly curing the rubber in a vulcanizing chamber. Thisstrip may be cut to the required lengths either before or after curingthe rubber covering II. The wax in the rubber forms a Water-repellentouter surface on theantenna strip during use. If desired in some cases,the rubber sheath may rst be prepared and cured and the metal stripinserted afterward but this is not the preferred way of making theantenna strip. If desired the metal antenna may be a flat braided Wireribbon or woven metal strip, or other types of metal strips may be usedso long as they are strong and flexible and capable of being threadedthrough the supports as hereinafter described.

The antenna proper thus prepared has one end thereof threaded through asuitable slot I2 in ie resilient insulating support I3 and has itsprojecting end doubled back upon itself and rmly clamped in place by thesmall metal clamp I4 as clearly shown in Fig. 3. The other end of theantenna IB is then threaded successively through slots I2 in the otherinsulator supports I3 and its other end may be suitably electricallyattached to a suitably shielded lead-in wire I which runs to the radioreceiving set in the automobile. The four insulators I3 shown in Fig. 1are attached to the front and rear hangers I6 for the running board(shown in plan outline at 9) by the metal hooks II as clearly shown inFig. 2. These hooks I'I each have an upturned hook I8 at one end whichis simply slipped through a hole I9 in the metal hanger I6 and held inplace therein by the tension in the resilient insulators I3. The otherend of each hook relatively wide at antenna strip I is supported ,bymetal coil tension springs and non-me- V2I thereof more securely retainsthe insulator I3 against slipping out of place. These hooks l 'l are soshaped as to properly space the antenna Y from the metal running boardthereabove to which the set is ordinarily grounded, and from the roadsurface therebelow and thus provide the maximum antenna eifect for radioreception and still provide suiiicient road clearance.

It will be noted that the antenna of this invention may be firstcompletely assembled with the resilient insulators I3 and hooks I'Iprior to attaching any parts to the running board or other parts of theautomobile. This assembly may then be easily and quickly secured to theautomobile simply by inserting the hooked ends I8 of hooks l1 into theholes I9 of the metal hanger IB at one end of the running board, andthen by slightly stretching the resilient connectors I3 the hooks I'Imay be similarly inserted into the holes I9 at the opposite end of therunning board. The tension remaining in the connectors I3 thereafterkeeps all the antenna strips lil uniformly stretched between the twohangers I6 and so prevents sagging of the strips Ill and rattling ofthehooks I'I and the vibration thereof will shake oi all mud, Water, ice,or snow. The resilient connectors I3 are preferably of waxcontainingresilient rubber reinforced by. pieces of heavy fabric 20 vulcanized tothe rubber so as to strengthen same at the end portions thereof andprevent the hooks I1 orantenna strip IU from tearing out their holes.YThe central portion of connectors I3 preferably has no fabric so thatthe rubber may stretch more readily under,

tension. Thus connectors I3 provide very eiiicient Water-repellantelectric insulator supports for the` antenna strip I and at the sametime serve as the tension springs therefor. Y

.This antenna assembly may be .easily made longer or shorter to suit anylength running board simply by using a greater or less length Vofantenna strip I0 when the same isassembled,

all the other Vparts remaining exactly the same.

lAlso insteadv of providing the three reaches of antenna strip I0 shownin Fig. 1 from the front to the rear hanger I 6, only one or two reachesmay readily be provided under each running board simply by assemblingthe stock parts IIJ, I3, I4, and I'l accordingly. Suitably located holesI9 may be easily drilled in the hangers I6 to properly locate thevarious reaches of the antenna strip Y I0 without any other change inthe running board. 'I'he reach adjacent the outer edge of the runningboard is the least shielded bythe car body hence provides the greatestantenna effect i The form of the invention shown in Figs. 5 and 6 willnow be described. In, this form the tallic spacer insulators 3l ofsufcient length 5- to properly space the ends of the antenna strip 6 I0from the metalsprings 3l] so as to avoidthe harmful electrical elfectduefto the antenna proper being too close at any point to groundedYVmetal parts.

Vpreferably made of rubber, either soft or hard These spacer insulators3| are rubber, with reinforcing fabric cords 32 in the center so thatYthe ring insulator 3l will stand pounded wth a, suflicient amount of asuitable wax, such as parain, which will exude H911; the

finished rubber insulator and form a moisture repellant film on itsouter surface at all times, which serves to keep these insulators 3|free of water lm at all times regardless'of the amount of water whichmay splash thereagainst during use. Heretofore it has been extremelydicult to properly protect a radio antenna supported under the runningboard or anywhere near the ground underan automobile from the veryharmful effects of water being splashed against. the antenna insulatorssince any change in the degree of insulation greatly changes thecapacity of the antenna. It has been found that the above describednon-metallic rubber and fabric insulators 3I containing wax compoundedwith the rubber solves this water problem in a remarkably efficientmanner.

Preferably, but not necessarily, these non-metallic insulators are madein the form of a ring so that the antenna strip lil may be readilythreaded therethrough at onerenrd thereof and a spring attachment loop35 threaded therethrough at the other end, as clearly shown in Figs. 5and 6. The attachment loop 35 preferably is a rubber covered flat stripofrmetal having its ends clamped together by a small metal grommet 34having a hole therethrough through which the end of tension spring 3|may be easily hooked. It is very convenient to use ashort length of therubber-covered antenna strip IB from which to make the attachment loop35, since both of these will then be of the same Width and t neatlywithin the spacer insulator 3|'.

This form of antenna may first be completely i) assembled with thesprings 30 and then be suitably attached to the under side of therunning board in the manner described for the first form. The outer endsof springs 3U may be simply hooked into holes in the Vrunning boardhangers I6, as above described, or if desired, depending verticallyadjustable brackets 40 may be provided for supporting the outer ends ofsprings 30, as shown vin Figsg and. 6. The coil tension springs 30 areof suflicient strength to maintain the antenna against sagging in themiddle vbut will yield if anything strikes the antenna and so minimizethe possibility of the antenna being torn loose or broken.

While it is preferable that the antenna strip proper be fully insulatedwith Vthe above described water-repellant rubber covering II, it hasbeen found that the antenna of this invention works very well if a baremetal strip be used provided the ends thereof be. properly insulatedwith water-repellant insulators in spaced Y relation with its endsupports as described in the above two forms. The strength andruggedness of construction of the entire antenna assembly permit it tosurvive very rough treatment, and its Water-repellant propertiesmaintain its electrical capacity substantiallyV constant even thoughwater, mud, ice or snow be splashed all over it. i

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming Within the scope of the claims whichfollow.

What is claimed is as follows:

1. A radio receiving antenna for automobiles mounted thereonnear theroad surface, said antenna comprising: a flexible harness-like structurehaving end attachment insulators and a flexible rubber-coated flatmetalV strip looped back and forth between said attachment insulatorsand forming a plurality of substantially longitudinally-extendinglaterally-spaced reaches and providing open spaces between said reachesto minimize the retention of Water, mud, or other foreign matter uponsaid antenna and the harmful capacity effect of such retention.

2. A radio receiving antenna for automobiles mounted thereon near theroad surface, said antenna comprising: a flexible harness-like structurehaving a plurality of laterally-spaced attachment insulators at eachopposed end thereof and a flexible rubber-coated flat metal strip loopedback and forth between said attachment insulators and thereby forming aplurality of substantially longitudinally-extending laterallyspacedreaches having open spaces therebetween.

3. A radio receiving antenna for automobiles mounted thereon near theroad surface, said antenna comprising: a flexible harness-like structurehaving attachment insulators at its opposed ends and a. flexible flatmetal strip individually coated with a water-repellant rubber coatingand looped back and forth between said attachment insulators and forminga plurality of longitudinally-extending laterallyspaced reaches, saidreaches being retained in substantially horizontal position bylongitudinal tension thereon.

4. A radio receiving antenna for automobiles mounted thereon near theroad surface, said antenna comprising: a unitary flexible structurehaving attachment insulators at its two opposed ends and a continuousflexible flat metal strip individually coated thruout its length with awater-repellant rubber coating, said rubbercoated metal strip stretchingback and forth between said attachment insulators and forming aplurality of longitudinal laterally-spaced reaches, each of said reachesof said continuous metal strip being connected to one of said attachmentinsulators at each opposed end thereof and held taut by said insulators.

5. In combination with an automotive vehicle, a radio antenna mountedupon the vehicle in such proximity to the road that it is subject to theharmful effects of rocks, gravel, sand, water, mud, or snow thrownagainst the antenna by the road Wheels of the vehicle, said antennacomprising: a plurality of spaced attachment insulators secured to saidvehicle, a continuous fiexible relatively flat metal strip individuallycoated thruout its length with a water-repellant rubber coating ofsubstantial thickness, said continuous strip stretching to and frobetween said attachment insulators and forming a plurality oflaterally-spaced reaches held in a taut horizontal position bylongitudinal tension in each of said reaches, said rubber coatingserving to insulate and protect said metal strip against physical damageby flying rocks, gravel or sand and also serving to substantiallyprevent adherence of a water lm from water splashed thereagainst fromthe road.

6. In combination with an automotive vehicle,

a radio antenna mounted upon the vehicle in r such proximity to the roadthat it is subject to the harmful effects of rocks, gravel, sand, water,mud, or snow thrown against the antenna by the road wheels of thevehicle, said antenna comprising: a main antenna element of metal heldstretched in substantially taut condition between two opposednon-metallic flexible supporting spacer links, said spacer linkscomprising resilient rubber reinforced with interior substantiallynon-stretchable fabric cords, said cords r

